JPS626983B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite steel plate with excellent vibration damping properties, and more particularly to a composite steel plate with excellent vibration damping properties in which a steel plate is glazed onto cast iron. The vibrations generated during the operation of various devices do not have a negative impact on the fatigue life of the structural materials of the devices themselves, but in recent years have become a subject of vibration and noise pollution problems, and there is a strong social focus on reducing and preventing them. Demand is being aroused.

In the past, various mechanical and acoustic engineering methods, including system damping, have been used to address these problems, in addition to passive measures to shield the generated vibrations and noise from the surrounding environment. However, basically, as a structural material for equipment that is a source of vibration, vibration damping properties (hereinafter also referred to as vibration damping properties) are used.
It can be said that it is a very effective method to reduce and prevent vibrations from occurring at the source by using so-called material damping, which utilizes excellent materials such as vibration damping materials. In applications where vibration damping materials are applied, their damping properties are often secondary to the original purpose of the device, and first of all, mechanical properties such as strength and workability are required. However,
Improving these properties generally tends to reduce damping properties, and this is the difficulty in developing excellent damping materials. Recently, there has been a strong interest in material damping, and various damping materials suitable for various purposes are being developed. Mn-Cu alloy and Fe-Cr alloy are generally well known as this type of material, but
For the former, the temperature range for good vibration damping is 50 to 80.
℃, the temperature range is very narrow, and both have the disadvantage that the damping properties deteriorate due to processing, and the latter is particularly significant. Composite materials made of organic materials clad with steel plates are also known to have excellent vibration damping properties, but it has been pointed out that this material also has problems with weldability and workability.

As such a vibration damping material, it has been well known for a long time that cast iron containing a large amount of highly developed flake graphite has a large vibration damping ability. However, this material had the disadvantages that cast iron had low strength and poor plastic workability, making it impossible to manufacture thin sheets.

An object of the present invention is to eliminate the above-mentioned drawbacks of conventional vibration damping materials and to provide a material having excellent vibration damping characteristics, that is, vibration damping properties.

The gist of the present invention is as follows.
In other words, the surface layer made of steel plate and the carbon equivalent = C
% + 1/3Si% of cast iron with a carbon equivalent of 3.0% or more, and an inner layer sandwiched by the surface layer, and the plate thickness ratio of the surface layer thickness of both sides to the total plate thickness. It is a composite steel plate with excellent vibration damping characteristics, characterized in that both are 5% or more.

The inventors of the present invention have conducted various research and experiments with the aim of effectively utilizing the excellent vibration damping properties of cast iron, and at the same time creating a material that can be made into thin plates through cold working. It has been found that the object of the present invention can be achieved by cladding the steel with ordinary steel or special steel.

The present invention will be explained in detail below.

As the material constituting the composite steel plate according to the present invention, a steel plate is used for the surface layer portion. Although there are no particular regulations regarding the composition, these surface layer members are mainly used to assist and improve the workability of the inner layer of cast iron, and materials that themselves have excellent workability as a single material are used. This is desirable. From the perspective of improving workability, the thickness ratio of the surface layer to the total thickness of a composite steel plate should be at least 5% on both sides; however, if the ratio is too large, workability will not be good. The result is that the damping properties of the cast iron in the center layer cannot be effectively utilized, so depending on the properties of the surface layer and the center,
It is desirable to keep it within the range of 25%. Further, the thickness of both surfaces of the surface layer portion may be different depending on necessity. When trying to obtain other properties as a surface member, such as corrosion resistance, stainless steel containing 11% or more of Cr should be used.If sufficient workability can be obtained as a composite steel plate, there is no hindrance to its use. It's not a thing. The vibration damping properties of this composite steel plate are determined by the properties of the cast iron that serves as the inner layer material, so it is necessary to appropriately select the carbon equivalent, which is closely related to the magnitude of vibration damping properties, depending on the usage date. When specifying carbon equivalent = C% + 1/3 Si, it is necessary that the carbon equivalent is 3.0% or more. This is because when the carbon equivalent is less than 3.0%, the vibration damping properties of the cast iron itself are low, and even after subsequent treatments such as cold rolling, it cannot be expected to improve much. Therefore, in the present invention, the lower limit of the carbon equivalent of the cast iron used is
The graphite shape of cast iron, limited to 0.3, can be flaky or spherical. The method of combining materials such as this, in which cast iron is used as an inner layer member and steel plates that hold it together as a surface layer, can be carried out by any method as long as the bond between both layers has sufficient mechanical strength. Good too. For example, cast iron cast to the required dimensions and shape is placed in the center of a mold and molten steel is poured around it, or the material is machined so that the thickness ratio of the surface layer to the inner layer is a predetermined value. After processing, the periphery may be welded and assembled. The composite material made as described above is heated to a temperature just below the melting point of the cast iron in the center layer, and then hot rolled. By this heating hot rolling, the two layers are joined at the interface.
If the application does not require a very large damping property, it can be used in the hot-rolled state, but if you want to obtain even better damping properties, the hot-rolled sheet should be appropriately annealed and cast iron can be used. It is recommended that the base be made into ferrite and then cold-rolled to a predetermined thickness before use.

Example 1 Inner layer material: C3.68%, Si2.74%, Mn0.91%
Using spheroidal graphite cast iron (carbon equivalent: 4.59) and ordinary steel containing 0.14% C, 0.21% Si, and 0.99% Mn as the surface material, the ratio of the inner layer to the total plate thickness was 95, 68,
60 and 47% (hereinafter referred to as samples A, B, C, and D, respectively), a composite material with a thickness of 25 mm was manufactured by machining, assembling, and welding the surrounding gap.
In addition, cast iron and ordinary steel with the same dimensions were also prepared as comparative materials, and comparative tests were conducted on these materials. These materials were heated at 1050° C. for 1 hour, then hot rolled to a thickness of 3 mm, annealed at 700° C. for 15 hours, and then cold rolled to a thickness of 0.6 mm. The comparative cast iron single material developed significant cracks at the end of hot rolling, making cold rolling impossible. On the other hand, regarding composite materials, sample A could be cold rolled to a thickness of 20 to 30%, and samples B, C, and D could be rolled to a thickness of 0.6 mm at a cold rolling rate of 80% without any problems. The internal wear value Q ^-1 of these materials at room temperature was measured using a transverse vibration internal friction measuring device, and their vibration damping properties were evaluated.

The internal wear value Q ^-1 is the value after exciting vibrations in the material.
It is defined as the value obtained by dividing the vibration energy attenuation rate per cycle during free damping by 2π (π: pi). For samples A, B, C, and D for hot-rolled sheets with a thickness of 3 mm, Q ^-1 at a strain amplitude of 3 x 10 ^-3 mm.
were 2.0, 1.0, 1.0, and 0.8×10 ^-3 , respectively.
At this time, in the case of only the surface material of ordinary steel, 0.3 ×
It was 10 ^-3 . In addition, samples B, C, and 0.6 mm thick cold-rolled sheets
D and Q ^-1 are respectively 7.0×10 ^-3 , 4.5×10 ^-3 and 3.3×
It was 10 ^-3 . Figure 1 shows the results of measuring the temperature dependence of vibration damping characteristics on a 0.6 mm thick cold-rolled material B using a torsional vibration type internal friction measuring device in the temperature range of -50 to 300°C. 9× at ~80℃
Although it shows a small maximum of 10 ^-3 , it maintains a value of 7.0×10 ^-3 or higher in the temperature range of 0 to 300°C. In addition, Figure 1 shows the case where a magnetic field of 300 oersted is applied (black circles) and the case where it is not applied (white circles), and it was found that there was no change at all in both cases, and no influence of the magnetic field was observed.

Example 2 Various ordinary cast irons with a carbon equivalent of 2.7 to 5.0 within the composition range of 2.5 to 4.5% C, 0.5 to 3.0% Si, and 0.3 to 1.2% Mn have a ratio of 60% to the total plate thickness. Like C0.14
%, Si 0.21%, Mn 0.99% common steel clad with a total plate thickness of 25 mm, and in the same manner as in Example 1 was made into a 3 mm thick hot rolled plate. The results of measuring the lateral vibration internal friction for these are shown in Figure 2. From Figure 2, as a guideline for damping performance, 0.8×
3.0 in carbon equivalent to obtain an internal attrition value of 10 ^-3 or higher.
It turns out that you need to do more than that.

In the present invention, a material with excellent vibration damping properties can be obtained by cladding cast iron with a carbon equivalent of 3.0% or more and a steel plate with a plate thickness ratio of 5% or more and rolling this.
We were able to achieve the effect of facilitating the development of future vibration damping equipment.

[Brief explanation of the drawing]

FIG. 1 is a correlation diagram showing the change in internal wear value of a 0.6 mm thick cold-rolled plate according to temperature in an example of a damping composite steel plate according to the present invention made of spheroidal graphite cast iron and ordinary steel;
FIG. 2 is a correlation diagram showing the relationship between carbon equivalent and internal wear value of a 3 mm thick hot rolled sheet in another example of the damping composite steel sheet of the present invention made of ordinary cast iron and ordinary steel.

Claims (1)

[Claims] 1 Surface layer portions on both sides made of steel plate and carbon equivalent = C
% + 1/3 S _i % The plate thickness is made of cast iron with a carbon equivalent of 3.0% or more, and is composed of an inner layer portion sandwiched by the surface layer portion, and the thickness of the surface layer portion on both sides relative to the total plate thickness. A composite steel plate with excellent vibration damping properties characterized by a ratio of 5% or more.